Friedrich wilhelm aschendorf



(No Model.)

' P. W. ASOHENDORR v 'BAKTRUMPET. No. 466,531. Patented Jan. 5, 1892.

UNITED STATES.

PATENT OFFICE.

FRIEDRICH WILHELM ASOHENDORF, OF WIESBADEN, GERMANY.

EAR-TRU M PET.

SPECIFICATION forming part of Letters Patent No. 466,531, dated January5, 1892.

Application filed July 6, 1891. Serial No. 398,616. (No model.)

To all whom it may concern:

Be it known that I, FRIEDRICH WILHELM AsOHENDORF, a resident ofWiesbaden, in the Kingdom of Prussia and German Empire,have

invented certain new and useful Improve ments in Ear-Trumpets; and I dohereby declare the following to be a full, clear,-and exact descriptionof the said invention, such as will enable those skilled in the art towhich it appertains to make and use the same.

My invention is an improvement in eartrumpets; and it consists in thenovel features hereinafter fully described.

In the accompanying drawings 1 have shown one form in which I havecontemplated embodying my invention, and the said invention is fullydisclosed in the following description and claims.

In the said drawings, Figure 1 represents a perspective View of anear-trumpet constructed according to my invention, and Fig. 2 representsa central longitudinal section of the same.

The object of my invention is to produce an ear-trumpet which shall besimple in con struction and which can be cheaply and easily made, andalso one which will have such a construction as to give a great amountof resonance.

In carrying out my invention I employ two shells or cones-an outer shell1 and an inner shell orconem-havingtheirlarge ends united,

by burnishing one over the other at n or by soldering or other preferredmeans. The outer shell or cone Z has an ear-piece or extension 19,adapted to fit the ear and having a passage through it communicatingwith the inclosed space 0 between the inner surfaces of the two shells.

The inner shell m is provided with a series (preferably three) of slotsor openings 0* r r, as shown in the drawings, which communicate with theinclosed space between the two shells. The inner shell is closed at qadjacent to the ear-piece p of the outer shell, as shown in Fig. 2. Bythis construction the sound undulations cannot pass into the open end ofthe inner shell and directly to the car through the ear-piecep, (theinner shell having no opening adjacent to the ear-piece, as beforestated,) but the sound will be forced to pass through the slots 4" r andbe communicated to the air inclosed between the walls of the shells,thereby causing the air in such inclosed space to vibrate and greatlyincreasing the resonance of the instrument. The walls of the shellsco-operating with the vibration of the air inclosed in the space betweensaid walls, will produce a resonance which will render the instrumentvery effective. It will also be seen that the instrument can be Verycheaply and easily manufactured. The tubular ear-piece 1) may be coveredwith iudia-rubber, leather, or other suitable substance to enable it tobe held in the ear without the support of the hand.

What I claim, and desire to secure by Letters Patent, is

'1. An ear-trumpet consisting of an outer and an inner shell having aninclosed space between, the inner shell having a series of aperturescommunicating with .the said space, and an ear-piece connected to theouter cone and communicating with said air-space at a distance from saidapertures, substantially as described.

2. An ear-trumpet consisting of an outer shell and an inner shell withinthe same, said shells having their larger ends connected together andforming an air space between them, an ear-piece secured to the outershell and communicating with the air-space adjacent to a closed portionof the inner shell, said inner shell having a series of apertures in thesame at a distance from saidear-piece, substantially as described.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

FRIEDRICH WILHELM ASOHENDORF. Witnesses:

ALVESTO P. HOGUE, JEAN GRUND.

